Following upgrading online last night to the 16GB offer, I phoned to ask when it would swap over to the new plan, and he said it should have automatically, so he said he could do it now in the phone, went through all the T&C, and it failed, he tried twice more and still failed to swap to the new plan and said there must be something wrong with my account but he can't understand what. Then someone said over his shoulder "that happened to me earlier", so he put me on hold, then came back said he'd just been speaking to his manager and apparently all day they've been having issues upgrading people to new sim only plans if they are already on an old sim only plan...
He said that they have to wait until it's fixed and he will try to do it again tomorrow without me having to phone again, he said if they can't do it over the next two days they will get back in touch
He seemed nice, and conscientious so I have no reason to doubt him, but there is a little part of me worrying there's just something wrong with my account and he just wanted to get me off the phone so it wasn't his problem.